<p>We carried out eight assessments of usability engineering processes in four industrial companies, for the purpose of providing a basis for process improvement. The research method was an empirical and iterative one: we carried out assessments, gathered data to understand the success criteria of assessments, and developed step by step an assessment method.</p> <p>The new assessment method has a new kind of process model and is implemented in workshops. The success criteria include issues such as: an assessment is expected to be an effective training occasion; the understandability of the concepts of an assessment approach and the results of an assessment are more important than a standard assessment approach; an assessment should focus on the usability engineering substance of processes rather than on the management of processes. Assessment maturity should be checked before a formal assessment is initiated.</p>